AES E-Library

AES E-Library

Input Current Requirements of High-Quality Loudspeaker Systems

Based on an analysis of the equivalent circuit of a multiway loudspeaker, the possibility of large drive currents is predicted for a class of non-sinusoidal band and amplitude-limited signals. The current builds up as coherent sum of two parts; charging of the driver reactances, and simultaneous current drain by several drivers. The input current of three commercial loudspeaker systems was measured using a signal derived from on the analysis. The results show that a loudspeaker may draw currents three to six times larger than those calculable from the rated speaker impedance. This indicates that certain generally accepted power amplifier design criteria should be reconsidered.